大孔径射孔器穿孔深度检测方法研究

指出了穿孔深度检测存在的缺陷，通过对大孔径射孔器井下使用环境要求、工作原理的分析，提出了对现行实验用混凝土靶进行改进的方案，并将穿孔深度指标的评价方法由计量抽样评价改为计数抽样评价，以克服穿孔深度检测过程中的缺陷．正确可靠地评价大孔径射孔器的性能。     

Local CEOs,career concerns and voluntary disclosure

I study whether the management guidance provided by local chief executive officers (CEOs) differs from the guidance provided by nonlocal CEOs. The geographic preferences of the CEOs lead to segmented executive labor markets, which impose higher relocation costs and give rise to lower job mobility. I find that local CEOs, who grew up in the same states where the firm headquarters are located, provide fewer items in guidance and less frequent guidance than nonlocal CEOs. I also show that local CEOs have greater asymmetric withholding of bad news relative to good news and that they increase their disclosure during economic downturns in their home states. Collectively, these findings suggest that the geographically segmented CEO labor markets play an important role in the disclosure choices of CEOs.     

The role of liquidity constraints in the response of monetary policy to house prices

We analyse the optimal response of monetary policy to house prices in a New Keynesian framework. A positive wealth effect from housing is derived from liquidity constrained consumers. Housing equity withdrawal allows them to convert an increase in housing value into consumption and we show that monetary policy should react to house prices due to their effect on consumption by constrained agents. Moreover, we allow the share of liquidity constrained consumers to vary with house prices. Consequently, the optimal weights on expected inflation, the output gap and house prices in the optimal interest rate rule vary over time too.     

一种基于FCME的跳频通信干扰检测门限设计方法

针对跳频卫星通信在应用中面临恶意干扰威胁的问题,需要对接收信号进行干扰检测。首先使用宽带能量检测模型对接收信号进行建模,分析了检测统计量的概率分布形式,其次在FCME算法以及恒虚警门限设置方法的基础上,利用概率统计知识分析高斯分布下部分样本与总体的关系,加入迭代修正过程对噪底进行估计以设置满足恒虚警概率要求的门限,最后利用Matlab搭建仿真平台进行仿真分析。理论和仿真分析表明,基于FCME的迭代修正门限设计方法相比于已有方法在SNR为0 dB、无干扰条件下能获得满足虚警概率要求的门限,当存在部分频带干扰时算法性能下降,但所获得的门限仍能满足虚警概率要求。设计方法在干扰较弱或不存在时能满足虚警概率要求,改善了FCME算法虚警概率偏高的情况,应用于跳频通信系统干扰检测的门限设计是可行的,在工程实际应用中有一定的参考价值。     

关于最佳现金持有量成本曲线模型分析

确定现金最佳持有量一直是企业流动资产管理研究的课题之一。本文在分析成本分析模型存在问题的基础上,提出了一个改进的成本曲线分析模型,并探讨了在不同环境下利用该模型求解最佳现金持有量及其对应的最低总成本的方法。     

Estimators for particulate sampling derived from a multinomial distribution

Counting the number of units is not always practical during the sampling of particulate materials: it is often much easier to sample a fixed volume or fixed mass of particles. Hence, a class of sampling designs is proposed which leads to samples that have approximately a constant mass or a constant volume. For these sampling designs, estimators were derived which are a ratio of arbitrary sample totals. A Taylor expansion was used to obtain a first-order approximation for the expected value and variance in the limit of a large batch-to-sample size ratio. Furthermore, a π -estimator for a ratio of batch totals was found by deriving expressions for the first- and second-order inclusion probabilities. Practical application of the π -estimator is limited because it requires inaccessible batch information. However, when the denominator of the estimated batch ratio is the batch size, the π -estimator becomes equal to a sample total divided by the sample size in the limit of a large sample-to-particle size ratio. As a consequence, the obtained sample ratio becomes an unbiased estimator for the corresponding batch ratio. Retaining unbiasedness, the Horvitz–Thompson estimator for the variance, which also contains inaccessible batch information, is replaced by an estimator containing sample information only. Practical application of this estimator is illustrated for the sampling of slag, produced during the production of steel.     

Return and volatility transmission between world oil prices and stock markets of the GCC countries

This paper investigates the return links and volatility transmission between oil and stock markets in the Gulf Cooperation Council (GCC) countries over the period 2005-2010. We employ a recent generalized VAR-GARCH approach which allows for transmissions in return and volatility. In addition, we analyze the optimal weights and hedge ratios for oil-stock portfolio holdings. On the whole, our results point to the existence of substantial return and volatility spillovers between world oil prices and GCC stock markets, and appear to be crucial for international portfolio management in the presence of oil price risk.     

RFID技术在物流中应用的探讨

射频识别技术是一种新兴的自动识别技术，正以其独有的优势向我们走来。本文简单介绍了射频识别技术，分析了在物流中应用RFTD技术会极大提高物流的效率，指出了它是现代物流信息化建设中基础数据获取的重要手段，从设备供应商和集成商两方面对系统的成功实施进行了分析评估。     

The genuine savings criterion and the value of population

Summary. In any dynamic model of the economy with changing population, the latter should properly be one of the state variables of the system. It enters both in the maximand, at least under total utilitarianism, and into the production function in one way or another. If population growth is exponential and constant returns prevails, then a simple transformation to per capita variables can be used to eliminate one state variable, but this ceases to be true if growth is not exponential, as it obviously is not and cannot be. If the growth of population is exogenous, then introducing it into the system does not affect the optimal policy. However, if one asks whether the system is sustainable, in the sense of at least maintaining total welfare (integral of discounted utilities), then the criterion is that that the value of the rates of change of the state variables is non-negative, so that the shadow price of population becomes relevant. In this paper, we derive explicit formulas in a simple model, showing that the rate of growth of per capita capital is not the correct formula but must have another terms added to it. We also study the question under an alternative criterion of long-run average utilitarianism. Received: June 1, 2002; revised version: September 27, 2002 RID="*" ID="*"Research support was provided by the William and Flora Hewlett Foundation. An earlier version of this paper was presented at a celebration of Mordecai Kurz's 66th birthday at Stanford University, 1–3 August 2002. Correspondence to: K.J. Arrow     

An optimal multiple stopping approach to infrastructure investment decisions

The energy and material processing industries are traditionally characterized by very large-scale physical capital that is custom-built with long lead times and long lifetimes. However, recent technological advancement in low-cost automation has made possible the parallel operation of large numbers of small-scale and modular production units. Amenable to mass-production, these units can be more rapidly deployed but they are also likely to have a much quicker turnover. Such a paradigm shift motivates the analysis of the combined effect of lead time and lifetime on infrastructure investment decisions. In order to value the underlying real option, we introduce an optimal multiple stopping approach that accounts for operational flexibility, delay induced by lead time, and multiple (finite/infinite) future investment opportunities. We provide an analytical characterization of the firm׳s value function and optimal stopping rule. This leads us to develop an iterative numerical scheme, and examine how the investment decisions depend on lead time and lifetime, as well as other parameters. Furthermore, our model can be used to analyze the critical investment cost that makes small-scale (short lead time, short lifetime) alternatives competitive with traditional large-scale infrastructure.